The present invention relates to a semiconductor device of a type having a supporting member for a semiconductor substrate in an electrically isolated manner therebetween.
Many kinds of semiconductor devices have supporting members not only for supporting the semiconductor substrate, but also to serve as an external electrode. One particular type of semiconductor device has been proposed in which the supporting member is electrically isolated from all the electrodes formed on the semiconductor substrate mainly for improving their adaptability in an electrical circuit. Such a semiconductor device will be referred to as a semiconductor device of the insulated type, or, more simply, as an insulated device in this specification. Hybrid ICs or semiconductor module devices are examples of such insulated devices. A discussion of such insulated devices can be found in U.S. Pat. No. 3,469,148.
On the other hand, it is required for a semiconductor device to dissipate heat generated in the semiconductor substrate while it operates through a support member for a safe and stable operation of the device. The heat flows from the semiconductor substrate to the atmosphere through various members therebetween. The semiconductor device of the insulated type is characterized by including an electrically insulating member in the path of the heat.
Some problems are found in semiconductor devices of the insulated type. These problems are, for example, poor conductivity of heat in the insulating layer, and large differences in the thermal expansion coefficients between the insulating layer and other members bonded thereto.